Boost convertor circuits have an electronic switch controlling the current through an inductor. When the current is switched off, a high voltage is created across the inductor which passes through a rectifier to charge a capacitor to a higher voltage than the original supply voltage.
They tend to be operated at a high switching frequency to reduce the absolute value and accordingly the size of the inductor. However, at each switching cycle there is a small reverse recovery current passing to the electronic switch because of the finite time taken for the charge recombination within the rectifier. There have been many proposals to prevent this current but all tend to suffer from various disadvantages which are exacerbated at higher output voltages because higher voltage rectifiers have a longer charge recombination time.
Prior attempts to prevent this reverse current from harming the electronic switch have involved using an inductor to prevent the reverse current flow and wasting the resulting energy in a resistor or in the inductor itself.